Stabilizers and antiozonants for elastomers

ABSTRACT

Elastomers which have excellent stability to prevent oxidative, thermal, dynamic, light-induced and/or ozone-induced degradation comprise, as stabilizers, at least one compound of the formula (I): [R—S(═O) m —CH 2 —CH(OH)—CH 2 ] n —N(R 1 ) 2−n —R 2 , in which R is C 4 -C 20 alkyl, hydroxyl-substituted C 4 -C 20 alkyl; phenyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl, cyclohexyl or —(CH 2 ) q COOR 3 , and, if m is 0, R may additionally be (a); and, if n is 1 and R 4  is hydrogen, R may additionally be R 2 —R 1 N—CH 2 —CH(OH)—CH 2 —S(═O) m —(CH 2 ) x — or R 2 —R 1 N—CH 2 —CH(OH)—CH 2 —S(═O) m —CH 2 —CH 2 —(OCH 2 —CH 2 ) y —, R 1  is hydrogen, cyclohexyl or C 3 -C 12 alkyl, R 2  is (b), R 3  is C 1 -C 18 alkyl, R 4  is hydrogen or —CH 2 —CH(OH)—CH 2 —S(═O) m —R, X is C 1 -C 8 alkyl, Y is C 1 -C 8 alkyl, m is 0 or 1, n is 1 or 2, q is 1 or 2, x is from 2 to 6, and y is 1 or 2. The compounds of the formula (I) are also suitable as stabilizes for elastomers to prevent contact discoloration of substrates coming into contact with elastomers.

The present invention relates to compositions comprising an elastomersusceptible to oxidative, thermal, dynamic, or light- and/orozone-induced degradation and, as stabilizer, at least one compound ofthe S-substituted4-(3-mercapto/sulfinyl-2-hydroxypropylamino)diphenylamine type, and alsoto the use of the stabilizers to prevent contact discoloration ofsubstrates coming into contact with elastomers, and as antiozonants forelastomers to prevent oxidative, thermal, dynamic, or light- and/orozone-induced degradation, and also to a process for preventing contactdiscoloration of substrates coming into contact with elastomers, and toa process for stabilizing elastomers, which comprises incorporating intothese, or applying to these, at least one compound of the S-substituted4-(3-mercapto/sulfinyl-2-hydroxypropylamino)diphenylamine type.

Rubber products (vulcanizates), like all polymers, are susceptible tooxidative, thermal, dynamic or light-induced degradation. A particularfactor causing damage to diene rubber vulcanizates is ozone. Ozoneattacks the carbon-carbon double bonds, of which many remain in therubber (vulcanizate), and, via the mechanism known as ozonolysis, causesdamage which is apparent as typical surface cracking, and failure of therubber product. The damage is particularly serious when the rubberproduct is under dynamic stress.

To prevent ozone damage, antioxidants selected from the class consistingof para-phenylenediamines [see Russel A. Mazzeo et al., “Tire TechnologyInternational” 1994, pp. 36-46; or Donald E. Miller et al., RubberWorld, 200 (5), 13-23 (1989)] are generally added to vulcanizates. Thesecompounds have very good protective action, especially under dynamicconditions, but develop a strong intrinsic colour (discolouring) and, asa result of high migration rate, these compounds give severe contactdiscoloration (staining), i.e. the dye transfers to othersubstrates/products on direct contact. This means that the stabilizersemployed in the prior art cannot be used as stabilizers for rubberproducts which are free from carbon black or are “non-black”, and theyare also unsuitable for (black) rubber products which comprise carbonblack and are intended for use in direct contact with pale-colouredproducts.

There continues, therefore, to be a need for colour-stable stabilizerswhich prevent ozone damage to rubber products, in particular topale-coloured rubber products. There also continues to be a need forstabilizers which, although they may have an intrinsic colour, areunable, for example as a result of chemical bonding to the rubberchains, to transfer the colour to other products.

The use of compounds of the 1-alkylthio-2-hydroxy-3-aminopropane type asstabilizers for lubricants, hydraulic fluids or metalworking fluids isknown from U.S. Pat. No. 4,863,621, for example.

It has now been found that compounds of the S-alkylated4-(3-mercapto/sulfinyl-2-hydroxypropylamino)diphenylamine type areparticularly suitable as stabilizers for elastomers susceptible tooxidative, thermal, dynamic, or light- and/or ozone-induced degradation.

The present invention therefore provides compositions comprising

a) a naturally occurring or synthetic elastomer susceptble to oxidative,thermal, dynamic, light-induced and/or ozone-induced degradation, and

b) as stabilizer, at least one compound of the formula I

[R—S(═O)_(m)—CH₂—CH(OH)—CH₂]_(n)—N(R¹)_(2−n)—R²  (I)

 in which

R is C₄-C₂₀alkyl, hydroxyl-substituted C₄-C₂₀alkyl; phenyl, benzyl,α-methylbenzyl, α,α-dimethylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³, and,if m is 0, R may additionally be

 and, it n is 1 and R⁴ is hydrogen, R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— or

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—,

R¹ is hydrogen, cyclohexyl or C₃-C₁₂alkyl,

R³is C₁-C₁₈alkyl,

R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R,

X is C₁-C₈alkyl,

Y is C₁-C₈alkyl,

m is 0 or 1,

n is 1 or 2,

q is 1 or 2,

x is from 2 to 6, and

y is 1 or 2.

Alkyl having up to 20 carbon atoms is a branched or unbranched radical,such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl,tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl,1,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl,1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl,2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl,decyl, undecyl, 1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl,tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl oreicosyl. One of the preferred meanings of R is C₄-C₂₀alkyl, inparticular C₆-C₁₂alkyl, e.g. C₈-C₁₂alkyl. A particularly preferredmeaning of R is tert-nonyl. One of the preferred meanings of R¹ isC₃-C₁₂alkyl, in particular C₃-C₈alkyl, e.g. C₃-C₆alkyl. A particularlypreferred meaning of R¹ is isopropyl or 1,3-dimethylbutyl. Aparticularly preferred meaning of R³ is C₁-C₁₈alkyl, in particularC₄-C₁₂alkyl, e.g. C₆-C₈alkyl. A preferred meaning of X and Y isC₁-C₈alkyl, in particular C₁-C₄alkyl, e.g. methyl or tert-butyl.

Hydroxyl-substituted C₄-C₂₀alkyl is a branched or unbranched radicalpreferably having from 1 to 3, in particular 1 or 2, hydroxyl groups,for example hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl,4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, 5-hydroxypentyl,4-hydroxypentyl, 3-hydroxypentyl, 2-hydroxypentyl, 6-hydroxyhexyl,5-hydroxyhexyl, 4-hydroxyhexyl, 3-hydroxyhexyl, 2-hydroxyhexyl,7-hydroxyheptyl, 6-hydroxyheptyl, 5-hydroxyheptyl, 4-hydroxyheptyl,3-hydroxyheptyl, 2-hydroxyheptyl, 8-hydroxyoctyl, 7-hydroxyoctyl,6-hydroxyoctyl, 5-hydroxyoctyl, 4-hydroxyoctyl, 3-hydroxyoctyl,2-hydroxyoctyl, 9-hydroxynonyl, 10-hydroxydecyl, 11-hydroxyundecyl,12-hydroxydodecyl, 13-hydroxytridecyl, 14-hydroxytetradecyl,15-hydroxypentadecyl, 16-hydroxyhexadecyl, 17-hydroxyheptadecyl,18-hydroxyoctadecyl or 20-hydroxyeicosyl. A preferred meaning of R ishydroxyl-substituted C₄-C₁₂alkyl, in particular hydroxyl-substitutedC₅-C₁₂alkyl, e.g. hydroxyl-substituted C₅-C₁₁alkyl.

Interesting compositions comprise, as component b), at least onecompound of the formula I in which, if n is 2, R and R³ have the samemeanings.

Preferred compositions comprise, as component b), at least one compoundof the formula I in which

R is C₄-C₁₂alkyl, hydroxyl-substituted C₄-C₁₂alkyl; benzyl,α-methylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³, and, if m is 0, R mayadditionally be

 and, if n is 1 and

R⁴ is hydrogen, R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— or

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—,

R¹ is hydrogen, cyclohexyl or C₃-C₈alkyl,

R³ is C₄-C₁₂alkyl,

X is C₁-C₄alkyl,

Y is C₁-C₄alkyl,

m is 0 or 1,

q is 1 or 2,

x is from 2 to 4, and

y is 1 or 2.

Preference is also given to compositions comprising, as component b), atleast one compound of the formula I in which

R is C₆-C₁₂alkyl, hydroxyl-substituted C₆-C₁₂alkyl; benzyl or—(CH₂)_(q)COOR³ ₁ and, if n is 1 and

R⁴ is hydrogen, R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— or

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂(OCH₂—CH₂)_(y)—,

R¹ is cyclohexyl or C₃-C₈alkyl,

R³ is C₆-C₁₀alkyl,

m is 0 or 1,

q is 1 or 2,

x is 2, and

y is 1 or 2.

Particular preference is given to compositions comprising, as componentb), at least one compound of the formula I in which

R is C₈-C₁₂alkyl or —(CH₂)_(q)COOR³, and, if n is 1 and R⁴ is hydrogen,R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—,

R¹ is isopropyl or 1,3-dimethylbutyl,

R³ is C₆-C₈alkyl,

R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R,

m is 0 or 1,

n is 1 or 2,

q is 1, and

y is 1 or 2.

Compounds of the formula I may, for example, be prepared in a mannersimilar to that of Example 1 disclosed in U.S. Pat. No. 4,863,621, byreacting the epoxides of the formula II with the amines of the formulaIII

The reaction takes place in the melt or in the presence of a suitableprotic or aprotic solvent, such as xylene, ethanol or 2-propanol. Thereaction preferably takes place in the presence of a suitable catalyst,e.g. salicylic acid or Fulcat 22B, in amounts of from 0.05 to 10%, inparticular 0.5 to 5%, based on the total weight of the compounds of theformulae II and III.

The reaction is carried out at temperatures of from 100 to 220° C., forexample, in particular at from 110 to 170° C., e.g. at from 120 to 150°C. During the reaction it is preferable for the compound of the formulaII to be used in a molar excess over the compound of the formula III. Aspecifically preferred molar ratio of the compound of the formula II tothe compound of the formula III is from 1.05:1 to 1.5:1.

The compounds of the formula I in which m is 1 (sulfoxides) may beobtained by known methods, for example, from the compounds of theformula I in which m is 0 (thioethers), by oxidation. An example of asuitable and specifically preferred oxidant is hydrogen peroxide.

Oxidation of the thioethers with an oxidant, such as hydrogen peroxide,can also give sulfinyl compounds which, in the case where n=2, have beenoxidized at only one sulfur. If the radical R⁴ contains sulfur,oxidation of this sulfur is also possible, and mixtures of compounds cantherefore be produced which have each been oxidized or not at theappropriate sulfur. All conceivable permutations are possible. Thesemixtures are likewise suitable as good stabilizers for elastomers, toprevent their oxidative, thermal, dynamic, or light- and/orozone-induced degradation, and/or as stabilizers to prevent contactdiscoloration of substrates coming into contact with elastomers.

The compounds of the formulae II and III are known from the literatureand are in some cases commercially available.

Component b) is suitable for stabilizing elastomers, in particularpale-coloured elastomers, to prevent oxidative, thermal, dynamic, orlight- and/or ozone-induced degradation.

Elastomers are to be understood as meaning macromolecular materialswhich after considerable deformation under a small load at roomtemperature rapidly regain approximately their original shape. See alsoHans-Georg Elias, “An Introduction to Polymer Science”, Section 12.“Elastomers”, pp. 388-393, 1997, VCH Verlagsgesellschaft mbH, Weinheim,Germany or “Ullmann's Encyclopedia of Industrial Chemistry, fifth,completely revised edition, Volume A 23”, pp. 221-440 (1993).

Examples of elastomers which may be present in the compositions of theinvention are the following materials:

1. Polymers of diolefins, for example polybutadiene or polylsoprene.

2. Copolymers of mono- and diolefins with one another or with othervinyl monomers, e.g. propylene-isobutylene copolymers,propylene-butadiene copolymers, isobutylene-isoprene copolymers,ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylatecopolymers, ethylene-vinyl acetate copolymers, acrylonitrile-butadienecopolymers, and also terpolymers of ethylene with propylene and with adiene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene.

3. Copolymers of styrene or α-methylstyrene with dienes or with acrylicderivatives, e.g. styrene-butadiene, styrene-butadiene-alkyl acrylateand styrene-butadiene-alkyl methacrylate; block copolymers of styrene,e.g. styrene-butadiene-styrene, styrene-isoprene-styrene andstyrene-ethylenebutylene-styrene, and also adhesives prepared from thelatter three.

4. Halogen-containing polymers, e.g. polychloroprene, chlorinatedrubber, chlorinated or brominated copolymer of isobutylene-isoprene(halobutyl rubber).

5. Natural rubber.

6. Aqueous emulsions of natural or synthetic rubbers, e.g. naturalrubber latex or latices of carboxylated styrene-butadiene copolymers.

The elastomers to be protected are preferably vulcanized elastomers. Ofparticular interest are natural rubber and synthetic rubber, andvulcanizates prepared therefrom. Particular preference is given topolydiene vulcanizates, halogen-containing polydiene vulcanizates,polydiene copolymer vulcanizates, in particular styrene-butadienecopolymer vulcanizates, and ethylene-propylene terpolymer vulcanizates.

Component b) is usefully added to the elastomer to be stabilized inamounts of from 0.05 to 10%, for example from 0.1 to 5%, preferably from0.5 to 3.0%, based on the weight of the elastomer to be stabilized.

In addition to components a) and b), the compositions of the inventionmay comprise other additives, such as the following:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linearor branched in the side chains, for example 2,6-di-nonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade-cyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis(3,5-di-tert-butyl-4-hydroxyphenyl)adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures thereof (vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methytphenol),4,4′-thiobis(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.

1.6. Alkylidenebisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenylterephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate,di-dodecylmercaptoethyl-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hydroxybenzyl compounds, for example1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyamino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyamino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.11. Benzylphosphonates, for exampledimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate,diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, thecalcium salt of the monoethyl ester of3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol,i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or poly-hydric alcohols, e.g. with methanol, ethanol,n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis-(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane;3,9-bis[2-{3-(3butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane.

1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3,5-di-tert-butyl-4-hydroxyhenyl acetic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide,N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide(Naugard® XL-1, supplied by Uniroyal).

1.18. Ascorbic acid (vitamin C)

1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetra-methyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono- anddialkylated nonyldiphenylamines, a mixture of mono- and dialkylateddodecyldiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamines, a mixture of mono- and dialkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylatedtert-octylphenothiazines, N-allylphenothiazine,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene.

2. UV absorbers and Light Stabilisers

2.1. 2-(2′-Hydroxyphenyl)benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol];the transesterification product of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300; [R—CH₂—CH₂—COO—CH₂CH₂₂, whereR=3′-tert-butyl-4′-hydroxy-5′-2H-benzotazol-2-ylphenyl,2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)phenyl]-benzotriazole;2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)-5′-(α,α-dimethylbenzyl)phenyl]benzotriazole.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxyand 2′-hydroxy-4,4′-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, for example4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoyl resorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methylα-cyano-β-methyl-p-methoxycinnamate, butylα-cyano-α-methyl-p-methoxycinnamate, methyl(α-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of2,2′-thiobis[4-(1,1,3,3-tetramethyl-butyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. themethyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, e.g. of2-hydroxy-4-methylphenylundecylketoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additionalligands.

2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl)succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate,the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-di-chloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,tetrakis(2,2,6,6-tetra-methyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione,bis(1-octyl-oxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(i-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cycliccondensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-diamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensate of1,2-bis(3-aminopropylamino)ethane and 2,4,6-tri-chloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); a condensate of 1,6-hexanediamine and2,4,6-trichloro-1,3,5-triazine as well as N,N-dibutylamine and4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [192268-64-7]);N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-di-aza-4-oxo-spiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]decaneand epichlorohydrin,1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,a diester of 4-methoxymethylenemalonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly(methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, areaction product of maleic acid anhydride-α-olefin copolymer with2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

2.7. Oxamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, mixtures of o- andp-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyl-oxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl-phenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazine,2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine,2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example N,N′-diphenyloxamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite,diphenylalkyl phosphites, phenyldialkyl phosphites,tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite,distearylpentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,4-di-cumylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,diisodecyloxypentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin,2,2′,2″-nitrilo-[triethyltris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite,5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane.

5. Hydroxylamines, for example N,N-dibenzylhydroxylamine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derivedfrom hydrogenated tallow amine.

6. Nitrones, for example N-benzyl-alpha-phenylnitrone,N-ethyl-alpha-methylnitrone, N-octyl-alpha-heptylnitrone,N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecylnitrone,N-hexadecyl-alpha-pentadecylnitrone,N-octadecyl-alpha-heptadecylnitrone,N-hexadecyl-alpha-heptadecylnitrone,N-ocatadecyl-alpha-pentadecylnitrone,N-heptadecyl-alpha-heptadecylnitrone,N-octadecyl-alpha-hexadecylnitrone, nitrone derived fromN,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

7. Thiosyneraistic compounds, for example thiodipropionic acid dilaurylester or thiodipropionic acid distearyl ester or compounds of formula IV

wherein

R₁ is hydrogen,

C₁-C₁₂alkyl, cyclohexyl, phenyl or benzyl,

R₂ is hydrogen or C₁-C₄alkyl, and

n is the number 0, 1 or 2.

8. Peroxide scavengers, for example esters of 0-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

9. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids, for example calciumstearate, zinc stearate, magnesium behenate, magnesium stearate, sodiumricinoleate and potassium palmitate, antimony pyrocatecholate or zincpyrocatecholate.

10. Nucleating agents, for example inorganic substances, such as talcum,metal oxides, such as titanium dioxide or magnesium oxide, phosphates,carbonates or sulfates of, preferably, alkaline earth metals; organiccompounds, such as mono- or polycarboxylic acids and the salts thereof,e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodiumsuccinate or sodium benzoate; polymeric compounds, such as ioniccopolymers (ionomers). Especially preferred are1,3:2,4-bis(3′,4′-dimethylbenzylidene)sorbitol,1,3:2,4-di(paramethyldibenzylidene)sorbitol, and1,3:2,4-di(benzylidene)sorbitol.

11. Fillers and reinforcing agents, for example calcium carbonate,silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica,barium sulfate, metal oxides and hydroxides, carbon black, graphite,wood flour and flours or fibers of other natural products, syntheticfibers.

12. Other additives, for example plasticisers, lubricants, emulsifiers,pigments, rheology additives, catalysts, flow-control agents, opticalbrighteners, flameproofing agents, antistatic agents and blowing agents.

13. Benzofuranones and indolinones, for example those disclosed in U.S.Pat. No. 4,325,863; U.S. Pat. No. 4,338,244; U.S. Pat. No. 5,175,312;U.S. Pat. No. 5,216,052; U.S. Pat. No. 5,252,643; DE-A-4316611;DE-A-4316622; DE-A-4316876; EP-A-0589839 or EP-A-0591102 or3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]-benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butylbenzo-furan-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one,3-(2,3-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one.

Preferred compositions of the invention comprise, as other additives,one or more components selected from the group consisting of pigments,dyes, fillers, levelling assistants, dispersants, plasticizers,vulcanization activators, vulcanization accelerators, vulcanizers,charge control agents, adhesion promoters, light stabilizers orantioxidants, such as phenolic antioxidants (items 1.1 to 1.18 in thelist) or aminic antioxidants (item 1.19 in the list), organic phosphitesor phosphonites (item 4 in the list) and/or thiosynergists (item 7 inthe list).

An example of the concentrations at which these other additives areadded is from 0.01 to 10%, based on the total weight of the elastomer tobe stabilized.

Component b), and also, if desired, other additives are incorporatedinto the elastomer by known methods, for example during mixing ininternal mixers with rams (Banbury), on mixing rolls or in mixingextruders, prior to or during shaping or vulcanization, or else byapplying dissolved or dispersed component b) to the elastomer, ifdesired with subsequent removal of the solvent by evaporation. Whenadded to the elastomer to be stabilized, component b) and, if desired,other additives may also be in the form of a masterbatch comprisingthese, for example at a concentration of from 2.5 to 25% by weight.

Component b) and, if desired, other additives may also be added prior toor during the polymerization of synthetic elastomers or prior tocrosslinking, i.e. advantageously, if desired, as a first-levelstabilizer in the crude rubber, which may also comprise othercomponents, such as carbon black as filler and/or extender oils.

The compounds of the formula I are bonded chemically to polymer chainsunder processing conditions (mixing, vulcanization, etc.). The compoundsof the formula I are resistant to extraction, i.e. they continue tooffer good protection after the substrate is subjected to intensiveextraction. The loss of compounds of the formula I from the elastomervia migration or extraction is extremely slight.

The elastomers stabilized with the compounds of the formula I also showmarkedly improved and desirable gloss. This means that the surface glossof the elastomer stabilized according to the invention, after exposureto ozone, is significantly higher than that of an unstabilized elastomeror of an elastomer stabilized in accordance with the prior art.

Component b) and, if desired, other additives may be in pure form orencapsulated in waxes, in oils or in polymers when they are incorporatedinto the elastomer to be stabilized.

Component b) and, if desired, other additives may also be sprayed ontothe elastomer to be stabilized. They are capable of diluting otheradditives (e.g. the conventional additives given above) or melts ofthese, and they may therefore also be sprayed together with theseadditives onto the elastomer to be stabilized.

The resultant stabilized elastomers may be used in a wide variety offorms, e.g. ribbons, moulding compositions, profiles, conveyor belts ortyres (pneumatic).

The present invention further provides a process for stabilizingelastomers to prevent oxidative, thermal, dynamic, light-induced and/orozone-induced degradation, which comprises incorporating into these orapplying to these at least one component b).

The present invention further provides a process for preventing contactdiscoloration of substrates coming into contact with elastomers, whichcomprises incorporating into the elastomers, or applying to these, atleast one component b).

A further embodiment of the present invention is the use of component b)as stabilizers for elastomers to prevent oxidative, thermal, dynamic,light-induced and/or ozone-induced degradation.

A further embodiment of the present invention is the use of component b)as stabilizers for elastomers to prevent contact discoloration ofsubstrates coming into contact with elastomers.

The preferred compounds of the formula I [component b)] for theprocesses and uses listed above are the same as those for thecompositions of the invention.

The present invention further provides novel compounds of the formula I

[R—S(═O)_(m)—CH₂—CH(OH)—CH₂]_(n)—N(R¹)_(2−n)—R²  (I),

in which

R is C₄-C₂₀alkyl, hydroxyl-substituted C₄-C₂₀alkyl; phenyl, benzyl,α-methylbenzyl, α,α-dimethylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³, and,if m is 0, R may additionally be

 and, if n is 1 and R⁴ is hydrogen, R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— or

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂(OCH₂—CH₂)_(y)—,

R¹ is hydrogen, cyclohexyl or C₃-C₁₂alkyl,

R³ is C₁-C₁₈alkyl,

R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R,

X is C₁-C₈alkyl,

Y is C₁-C₈alkyl,

m is 0 or 1,

n is 1 or 2,

q is 1 or 2,

x is from 2 to 6, and

y is 1 or 2; with the proviso that the compound of the formula Ia

is excluded.

The preferred meanings of the general symbols in the novel compounds ofthe formula I are the same as the preferred meanings of the generalsymbols set out in relation to the compositions of the invention.

Interesting novel compounds of the formula I are those in which

R is C₄-C₂₀akyl, hydroxyl-substituted C₄-C₂₀alkyl; phenyl, benzyl,α-methylbenzyl, α,α-dimethylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³,

R¹ is hydrogen, cyclohexyl or C₃-C₁₂alkyl,

R³ is C₁-C₁₈alkyl,

R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R,

m is 0 or 1,

n is 1 or 2, and

q is 1 or 2, with the proviso that the compound of the formula Ia isexcluded.

Preferred novel compounds of the formula I are those in which

R is C₈-C₁₂alkyl or —(CH₂)_(q)COOR³, and, if n is 1 and R⁴ is hydrogen,R may additionally be

R²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—,

R¹ is isopropyl or 1,3-dimethylbutyl,

R³ is C₆-C₈alkyl,

R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R,

m is 0 or 1,

n is 1 or 2,

q is 1, and

y is 1 or 2, with the proviso that the compound of the formula Ia isexcluded.

The examples below further illustrate the invention. Data in parts orpercentages are based on weight.

EXAMPLE 1 Preparation of4-{N-isopropyl-N-[3-(n-octylthio)-2-hydroxypropyl]amino}diphenylamine(Compound 101, Table 1)

A mixture of glycidyl n-octyl thioether (31.6 g) and4-isopropylaminodiphenylamine [27.2 g, Vulkanox 4010 (RTM), Bayer] andsalicylic acid (0.8 g) is stirred for 8 hours at 150° C. The reactionmixture is diluted with hexane and washed with saturated sodiumcarbonate solution and water. Concentration of the organic phase byevaporation followed by drying at 220° C./0.02 mbar gives 51.2 g (99.5%)of 4-{N-isopropyl-N-[3-(n-octylthio)-2-hydroxypropyl]amino}diphenylamine(compound 101, Table 1) as a viscous oil. Empirical formula C₂₆H₄₀N₂OS(428.68). Analysis calculated: C, 72.85; H, 9.41; N, 6.53; S, 7.48%.Analysis found: C, 71.94; H, 9.63; N, 5.87; S, 7.86%. EI-MS: 428 (M⁺),239 (M minus the radical octyl-SCH₂CH(OH), base peak).

In a manner similar to that of Example 1 and using glycidyl tert-nonylthioether instead of glycidyl n-octyl thioether, 98% of4-{N-isopropyl-N-[3-(tert-nonylthio)-2-hydroxypropyl]-amino}diphenylamine(compound 102, Table 1) is obtained as a viscous oil. Molecular weightC₂₇H₄₂N₂OS (M 442.71). Analysis calculated: C, 73.25; H, 9.56; N, 6.33;S, 7.24%. Analysis found: C, 73.21; H, 9.70; N, 6.26; S, 7.33%. EI-MS:442 (M⁺), 239 (M minus tert-nonyl-SCH₂CH(OH), base peak).

Again, in a manner similar to that of Example 1 and using glycidyln-dodecyl thioether, glycidyl tert-dodecyl thioether or glycidylisooctyloxycarbonylmethyl thioether instead of glycidyl n-octylthioether, compounds 103, 104 and 111 (Table 1) are prepared.

In a manner similar to that of Example 1 and using4-(1,3-dimethylbutylamino)diphenylamine instead of4-isopropylaminodiphenylamine, compound 107 (Table 1) is obtained.Additionally replacing glycidyl n-octyl thioether with glycidyln-dodecyl thioether, glycidyl tert-dodecyl thioether or glycidyltert-nonyl thioether gives compounds 105, 106 and 108 (Table 1).

In a manner similar to that of Example 1, the reaction of glycidyln-dodecyl thioether with 4-(2-octylamino)diphenylamine gives compound109 (Table 1). Again in a manner similar to that of Example 1, thereaction of glycidyl n-dodecyl thioether with4-cyclohexylaminodiphenylamine gives compound 110 (Table 1).

TABLE 1

Com- pound R R¹ Constitution M⁺ 101 n-octyl isopropyl viscous oil 428102 tert-nonyl isopropyl viscous oii 442 103 n-dodecyl isopropyl brownmass 484 104 tert-dodecyl isopropyl viscous oil 484 105 n-dodecyl1,3-dimethylbutyl dark brown 526 oil 106 tert-dodecyl 1,3-dimethylbutyldark brown 526 oil 107 n-octyl 1,3-dimethylbutyl dark brown 470 oil 108tert-nonyl 1,3-dimethylbutyl dark brown 484 resin 109 n-dodecyl 2-octyldark brown 554 resin 110 n-dodecyl cyclohexyl dark brown 524 resin 111iso-C₈H₁₇OOCCH₂— isopropyl dark brown 486 oil

EXAMPLE 2 Preparation of4-{N-isopropyl-N-[3-(n-octylsulfinyl)-2-hydroxypropyl]amino}diphenylamine (Compound 201, Table 2)

4.53 g of 30% strength aqueous hydrogen peroxide solution (H₂O₂) areadded to a solution of 10 g of compound 101 (Example 1, Table 1) in 25ml of acetone. The reaction mixture is stirred for 9 hours at 40° C. Thereaction mixture is then treated with 100 ml of water and 50 ml oftolene. Most of the acetone is distilled off on a rotary evaporatorunder suction. The organic phase is separated off, washed with water,dried over sodium sulfate and concentrated by evaporation on a rotaryevaporator under suction. Chromatography of the residue on silica gelwith hexane/ethyl acetate/ethanol (12:7:1) gives 7.14 g (69%) of4-{N-isopropyl-N-[3-(n-octylsulfinyl)-2-hydroxypropyl]amino}diphenylamine(compound 201, Table 2), brownish resin, molecular weight C₂₆H₄₀N₂O₂S(444.68). Analysis calculated: C, 70.23; H, 9.07; N, 6.30; S, 7.21%.Analysis found: C, 70.04; H, 9.04; N, 6.42; S, 7.05%. EI-MS: 444 (M⁺),239 (M minus octyl-S(═O)CH₂CH(OH), base peak).

In a manner similar to that of Example 2 and using compound 102 (Example1, Table 1), 62% of4-{N-isopropyl-N-[3-(tert-nonylsulfinyl)-2-hydroxypropyl]amino}diphenylaminecompound 202, Table 2) is obtained as a brownish resin. Molecular weightC₂₇H₄₂N₂O₂S Analysis calculated: C, 70.70; H, 9.23; N, 6.11; S, 6.99%.Analysis found: C, 70.84; H, 9.19; N, 6.05; S, 7.35%. EI-MS: 458 (M⁺),332 (M minus C₉H₁₈), 239 (M minus tert-nonyl-S(═O)CH₂CH(OH), base peak).

In a manner similar to that of Example 2 and using compounds 103 to 111(Example 1, Table 1), compounds 203 to 211 (Table 2) are obtained.

TABLE 2

Com- pound R R¹ Constitution M⁺ 201 n-octyl isopropyl brownish 444 resin202 tert-nonyl isopropyl brownish 458 resin 203 n-dodecyl isopropylmelting 500 point 48° C. 204 tert-dodecyl isopropyl viscous oil 500 205n-dodecyl 1,3-dimethylbutyl dark brown 542 oil 206 tert-dodecyl1,3-dimethylbutyl dark brown 542 oil 207 n-octyl 1,3-dimethylbutyl darkbrown 486 oil 208 tert-nonyl 1,3-dimethylbutyl dark brown 500 resin 209n-dodecyl 2-octyl dark brown 570 resin 210 n-dodecyl cyclohexyl darkbrown 540 resin 211 iso-C₈H₁₇OOCCH₂— isopropyl dark brown 502 oil

EXAMPLE 3 Preparation of4,13-dithia-7,10-dioxa-1,16-bis[N-isopropyl-4-(phenylamino)-anilino]-2,15-dihydroxyhexadecane(Compound 301)

20.6 g (0.07 mol) of bisglycidyl thioether of3,6-dioxa-1,8-octanedithiol are added dropwise over a period of 2 hoursat 150° C. to 22.6 g (0.10 mol) of 4-isopropylaminodiphenylamine[Vulkanox 4010 (RTM), Bayer] and 0.28 g (2 mmol) of salicylic acid. Thereaction mixture is then stirred for a further 6 hours at 150° C. Thereaction mixture is cooled and chromatographed on silica gel using ethylacetate/hexane (1:1). The pure fractions are combined, and the solventis removed by evaporation on a rotary evaporator with suction. Thisgives 13.25 g (36%) of4,13-dithia-7,10-dioxa-1,16-bis-[N-isopropyl-4-(phenylamino)anilino]-2,15-dihydroxyhexadecane(compound 301), viscous oil. Empirical formula C₄₂HSBN₄O₄S₂ (747.08).Analysis calculated: C, 67.52; H, 7.83; N, 7.50; S, 8.58%. Analysisfound: C, 67.58; H, 7.78; N, 7.21; S, 7.93%. EI-MS: 746 (M⁺), 239(C₆H₅NHC₆H₄N(C₃H₇)CH₂ ⁺, base peak).

EXAMPLE 4 Preparation of Compound 302

17.5 g (0.07 mol) of bisglycidyl thioether of 3-oxa-1,5-pentanedithiolare added dropwise over a period of 2 hours at 150° C. to 22.6 g (0.10mol) of 4-isopropylaminodiphenylamine [Vulkanox 4010 (RTM), Bayer] and0.28 g (2 mmol) of salicylic acid. The reaction mixture is then stirredfor a further 6 hours at 150° C. The reaction mixture is cooled andchromatographed on silica gel using ethyl acetate/hexane (1:1). The purefractions are combined, and the solvent is removed by evaporation on arotary evaporator with suction. This gives 37.0 g (92%) of compound 302,viscous oil. EI-MS: 702 (M⁺), 239 (C₆H₅NHC₆H₄N(C₃H₇)CH₂ ⁺; base peak).

EXAMPLE 5 Preparation of Compound 303

28.1 g (0.13 mol) of glycidyl tert-nonyl thioether are added dropwiseover a period of 2 hours at 150° C. to 9.2 g (0.05 mol) of4-aminodiphenylamine and 0.14 g (1 mmol) of salicylic acid. The reactionmixture is then stirred for a further 2 days at 150° C. The reactionmixture is cooled and chromatographed on silica gel using ethylacetate/hexane (1:3). The pure fractions are combined, and the solventis removed by evaporation on a rotary evaporator with suction. Thisgives 6.1 g (16.5%) of compound 303, viscous oil. Empirical formulaC₄H8N₂O₃S₃ (833.40). Analysis calculated: C, 69.23; H, 10.09; N, 3.36;S, 11.53%. Analysis found: C, 68.83; H, 10.09; N, 3.54; S, 11.68%.CI-MS: 833 (M⁺), 127 (C₉H₁₉ ⁺; base peak).

EXAMPLE 6 Stabilization of Black Vulcanizate

40.0 parts by weight of Cariflexs 1220 [polybutadiene, SHELL] areprocessed on mixing rolls at 60° C. with 60.0 parts by weight of naturalrubber and 55.0 parts by weight of carbon black (N 330), 6.0 parts byweight of Ingralen 450 (RTM) [extender oil], 5.0 parts by weight of zincoxide [vulcanization activator], 2.0 parts by weight of stearic acid[vulcanization activator], 0.2 parts by weight of IRGANOX 1520 (RTM)[processing stabilizer, Ciba Spezialitätenchemiel, 2.0 parts by weightof sulfur (vulcanizer), 0.6 part by weight of Vulkacit MOZ (RTM)[vulcanization accelerator, BAYER] and 2.0 parts by weight of thestabilizer to be tested in accordance with Table 3, to give ahomogeneous mixture, the vulcanization system (sulfur and Vulkacit MOZ(RTM)] not being added until the end of the mixing process. The mixtureis vulcanized in electrical heating presses at 150° C. to T95 on therheometer curves, to give elastomer sheets of 2 mm thickness, 21 cmlength and 8.0 cm width. Sections of the 2 mm rubber sheets are placedon a white cardboard underlay and stored in a circulating-air cabinet at50° C. for 5 days. The contact surface or its margin is then evaluatedvisually for contact discoloration (staining): 0=no discoloration (orthe discoloration of the reference in which no AO is present) and5=greatest degree of discoloration. The slighter the contactdiscoloration, the better the stabilization. The results are given inTable 3.

TABLE 3 Stabilizer Contact Example (compound) discoloration - visual6a^(a)) — 0 6b^(a)) Vulkanox 4020 (RTM)^(c)) 5 6c^(b)) 103 0-1 6d^(b))106 0-1 6e^(b)) 107 0-1 6f^(b)) 108 0-1 6g^(b)) 109 0-1 6h^(b)) 110 0-16i^(b)) 111 0-1 6k^(b)) 203 0-1 6l^(b)) 205 0-1 6m^(b)) 206 0-1 6n^(b))210 0-1 ^(a))Comparative example ^(b))Inventive example ^(c))Vulkanox4020 (RTM) [Bayer] is 4-[1,3-dimethylbutyl]aminodiphenylamine of theformula A (A)

What is claimed is:
 1. A composition comprising a) a naturally occurringor synthetic elastomer susceptible to oxidative, thermal, dynamic,light-induced and/or ozone-induced degradation, and b) as stabilizer, atleast one compound of the formula I[R—S(═O)_(m)—CH₂—CH(OH)—CH₂]_(n)—N(R¹)_(2−n)—R²  (I),  in which R isC₄-C₂₀alkyl, hydroxyl-substituted C₄-C₂₀alkyl; phenyl, benzyl,α-methylbenzyl, α,α-dimethylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³, and,if m is 0, R may additionally

 and, if n is 1 and R⁴ is hydrogen, R may additionally beR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— orR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(OCH₂—CH₂)_(y)—, R¹ is hydrogen,cyclohexyl or C₃-C₁₂alkyl,

R³ is C₁-C₁₈alkyl, R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R, X isC₁-C₈alkyl, Y is C₁-C₈alkyl, m is 0 or 1, n is 1 or 2, q is 1 or 2, x isfrom 2 to 6, and y is 1 or
 2. 2. A composition according to claim 1, inwhich R is C₄-C₁₂alkyl, hydroxyl-substituted C₄-C₁₂alkyl; benzyl,α-methylbenzyl, cyclohexyl or —(CH₂)_(q)COOR³, and, if m is 0, R mayadditionally be

 and, if n is 1 and R⁴ is hydrogen, R may additionally beR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— orR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—, R¹ ishydrogen, cyclohexyl or C₃-C₈alkyl, R³ is C₄-C₁₂alkyl, X is C₁-C₄alkyl,Y is C₁-C₄alkyl, m is 0 or 1, q is 1 or 2, x is from 2 to 4, and y is 1or
 2. 3. A composition according to claim 1, in which R is C₆-C₁₂alkyl,hydroxyl-substituted C₆-C₁₂alkyl; benzyl or —(CH₂)_(q)COOR³, and, if nis 1 and R⁴ is hydrogen, R may additionally beR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—(CH₂)_(x)— orR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂(O—CH₂—CH₂)_(y)—, R¹ iscyclohexyl or C₃-C₆alkyl, R³ is C₆-C₁₀alkyl, m is 0 or 1, q is 1 or 2, xis 2, and y is 1 or
 2. 4. A composition according to claim 1, in which Ris C₈-C₁₂alkyl or —(CH₂)_(q)COOR³, and, if n is 1 and R⁴ is hydrogen, Rmay additionally beR²—R¹N—CH₂—CH(OH)—CH₂—S(═O)_(m)—CH₂—CH₂—(O—CH₂—CH₂)_(y)—, R¹ isisopropyl or 1,3-dimethylbutyl,

R³ is C₆-C₈alkyl, R⁴ is hydrogen or —CH₂—CH(OH)—CH₂—S(═O)_(m)—R, m is 0or 1, n is 1 or 2, q is 1, and y is 1 or
 2. 5. A composition accordingto claim 1, in which component a) is a carbon black free elastomer.
 6. Acomposition according to claim 1, in which component a) is a natural orsynthetic rubber or vulcanizates prepared therefrom.
 7. A compositionaccording to claim 1, in which component a) is a polydiene vulcanizate,a halogen-containing polydiene vulcanizate, a polydiene copolymervulcanizate or an ethylene-propylene terpolymer vulcanizate.
 8. Acomposition according to claim 1, comprising other additives in additionto components a) and b).
 9. A composition according to claim 8,comprising, as other additives, one or more components selected from thegroup consisting of pigments, dyes, fillers, levelling assistants,dispersants, plasticizers, vulcanization activators, vulcanizationaccelerators, vulcanizers, charge control agents, adhesion promoters,antioxidants and light stabilizers.
 10. A composition according to claim8, comprising, as other additives, phenolic antioxidants, aminicantioxidants, organic phosphites or phosphonites and/or thio-synergists.11. A composition according to claim 1, in which the amount of componentb) present is from 0.05 to 10%, based on the weight of component a). 12.A process for stabilizing elastomers to prevent oxidative, thermal,dynamic, light-induced and/or ozone-induced degradation, which comprisesincorporating therein or applying thereto at least one component b)according to claim
 1. 13. A process for preventing contact discolorationof substrates coming into contact with elastomers, which comprisesincorporating into the elastomers, or applying thereto, at least onecomponent b) according to claim 1.